1. Field of the Invention
The present invention relates generally to apparatus and methods for use in surgical removal of cancerous tumors.
2. Description of the Prior Art
As early as 1885, Gerster reported that surgical treatment for cancer might actually result in further dissemination of the disease. N.Y. Med. J. 41: 233-6 (1885). Wexner, et. al., reported that tumor formation at port sites following laparoscopic colorectal surgery is common. However, recurrences have not been limited to the port through which the specimen was retrieved, indicating that laparoscopic specimen bags or "wound protectors" are not sufficient to protect against "seeding" of exfoliated tumor cells. Brit.J.Surg. 82: 295-8 (1995). Tumor recurrence within trocar sites strongly suggests that the laparoscopic surgery itself may contribute to the dissemination of tumor cells into the peritoneal cavity. Sugarbaker, Surg.Endosc. 10: 295-6 (1996). The potential for tumor cell exfoliation and seeding is not limited to laparoscopic techniques, however, and Umpleby, et. al. have shown that large numbers of apparently viable tumor cells can be retrieved from the lumen of the large intestine after surgical resection. Brit. J.Surg. 71: 659-63 (1984).
Surgical resection of tumors often involves extensive manipulation of the resected specimen and the surrounding tissues due to limited space and tactile response. This provides an increased opportunity for exfoliation of tumor cells, with subsequent spread of those cells to other sites.
Tumor-laden instruments may also deposit cells into incisions. Nduka, et. al., Brit.J.Surg. 81: 648-52 (1994). Malignant cells have been shown to collect on both open and laparoscopic surgical instruments. Dis. Colon Rectum 35: 238-42 (1992). Furthermore, passage of resected tissue through the incision may coat the wound with exfoliated, potentially malignant cells. Nduka, Brit.J.Surg. 81: 648-52 (1994). To decrease the number of cells seeded into the wound in this manner, impermeable bags have been used to isolate the resected specimen from the surrounding tissue before removing it through the surgical incision.
However, this technique only minimizes seeding at the site of specimen removal, while exfoliated cells may be transported to and deposited at other sites. To address this problem, intraperitoneal chemotherapy has been employed with some success. Sugarbaker, World J. Surg. 19: 235-40 (1995). Fisher, et al., reported that the most effective chemotherapy application would be to use the largest tolerable dose at the time of or before primary tumor removal. Cancer Res. 43: 1488-92 (1983).
Two mechanisms have been proposed whereby chemotherapy may reduce tumor cell implantation: (1) cytotoxic effects on the tumor cells themselves, and (2) slowing down the wound healing process, reducing tumor cell entrapment. Jacquest, et. al., Wounds 7(2): 40-47 (1995). Early postoperative intraperitoneal chemotherapy has been proposed because, as adhesions form, viable cancer cells are trapped in a fibrin bundle--excluding the chemotherapeutic agent from the region. Sugarbaker, World J.Surg. 19: 235-40 (1995). Early events in wound healing play a role in tumor cell implantation, as suggested by the fact that the frequency of tumor implantation in injured sites was shown to decrease over time after tumor cell presentation. Sugarbaker, et. al., reported that intraperitoneal delivery of the chemotherapeutic agent 5-fluorouracil increased the dosage that could be tolerated without adverse side effects, and produced fewer hematologic toxicity reactions than lower doses given by the intravenous route. 98: 414-21(1985).
Franklin, et al., "Prospective comparison of open versus laparoscopic colon surgery for carcinoma: Five Year Results", (1996) reported that no trocar site implantations nor wound implantations were found in 215 patients followed from June 1990 through March 1996 after laparoscopic colon surgery for carcinoma using the following measures: (1) bagging of specimens prior to removal, (2) washing the trocar with povidone-iodine prior to removal, (3) removing intra-abdominal fluid to prevent tumor-laden fluid from bathing the wound, (4) removing insufflated gas prior to trocar removal, (5) irrigating the skin and subcutaneous sites with povidone-iodine prior to closure, (6) taking special care to avoid chipping or direct handling of the tumor, and (7) wound closure at the trocar site immediately after surgery. These results indicate that no single measure is sufficient to prevent the spread of exfoliated cells after surgical resection, and that proper preventive measures require a combination of techniques designed to minimize exfoliation and attachment of tumor cells at other sites.
Additionally, the prior art includes irrigation devices having fluid flow passages designed for irrigation of a surgical site. Prior art references which relate generally to such apparatus include the following:
U.S. Pat. No. 4,747,820 to Hornlein, et al. PA1 U.S. Pat. No. 5,125,910 to Freitas PA1 U.S. Pat. No. 5,197,948 to Ghodsian PA1 U.S. Pat. No. 5,607,391 to Klinger, et al. PA1 U.S. Pat. No. 4,846,790 to Hornlein, et al. PA1 U.S. Pat. No. 5,186,714 to Boudreault, et al.
Thus, it is seen that there is a continuing need for improved apparatus and methods for minimizing the recurrence of cancerous tumors after cancer surgery.